Abnormal immunity of non-survivors with COVID-19: predictors for mortality

Background The number of coronavirus disease 2019(COVID-19)cases has rapidly increased all over the world.Specific information about immunity in non-survivors with COVID-19 is scarce.This study aimed to analyse the clinical characteristics and abnormal immunity of the confirmed COVID-19 non-survivors.Methods In this single-centered,retrospective,observational study,we enrolled 125 patients with COVID-19 who were died between January 13 and March 4,2020 in Renmin Hospital of Wuhan University.A total of 414 randomly recruited patients with confirmed COVID-19 who were discharged from the same hospital during the same period served as control.The demographic,clinical characteristics and laboratory findings at admission,and treatment used in these patients were collected.The immunity-related risk factors associated with in-hospital death were tested by logistic regression models and Receiver Operating Characteristic(ROC)curve.Results Non-survivors(70 years,IQR:61.5–80)were significantly older than survivors(54 years,IQR:37–65)(P<0.001).56.8%of non-survivors was male.Nearly half of the patients(44.9%)had chronic medical illness.In non-survivors,hypertension(49.6%)was the most common comorbidity,followed by diabetes(20.0%)and coronary heart disease(16.0%).The common signs and symptoms at admission of non-survivors were fever(88%),followed by cough(64.8%),dyspnea(62.4%),fatigue(62.4%)and chest tightness(58.4%).Compared with survivors,non-survivors had higher white blood cell(WBC)count(7.85 vs 5.07×109/L),more elevated neutrophil count(6.41 vs 3.08×109/L),smaller lymphocyte count(0.69 vs 1.20×109/L)and lower platelet count(172 vs 211×109/L),raised concentrations of procalcitonin(0.21 vs 0.06 ng/mL)and CRP(70.5 vs 7.2 mg/L)(P<0.001).This was accompanied with significantly decreased levels of CD3+T cells(277 vs 814 cells/μl),CD4+T cells(172 vs 473 cells/μl),CD8+T cells(84 vs 262.5 cells/μl,P<0.001),CD19+T cells(88 vs 141 cells/μl)and CD16+56+T cells(79 vs 128.5 cells/μl)(P<0.001).The concentrations of immunoglobulins(Ig)G(13.30 vs 11.95 g/L),IgA(2.54 vs 2.21 g/L),and IgE(71.30 vs 42.25 IU/ml)were increased,whereas the levels of complement proteins(C)3(0.89 vs 0.99 g/L)and C4(0.22 vs 0.24 g/L)were decreased in non-survivors when compared with survivors(all P<0.05).The non-survivors presented lower levels of oximetry saturation(90 vs 97%)at rest and lactate(2.40 vs 1.90 mmol/L)(P<0.001).Old age,comorbidity of malignant tumor,neutrophilia,lymphocytopenia,low CD4+T cells,decreased C3,and low oximetry saturation were the risk factors of death in patients with confirmed COVID-19.The frequency of CD4+T cells positively correlated with the numbers of lymphocytes(r=0.787)and the level of oximetry saturation(r=0.295),Whereas CD4+T cells were negatively correlated with age(r=-0.323)and the numbers of neutrophils(r=−0.244)(all P<0.001).Conclusions Abnormal cellular immunity and humoral immunity were key features of non-survivors with COVID-19.Neutrophilia,lymphocytopenia,low CD4+T cells,and decreased C3 were immunity-related risk factors predicting mortality of patients with COVID-19.